James M. Thorne

Laser-induced thermal lens effect: a new theoretical model

A theoretical model for the laser-induced thermal lens effect in weakly absorbing media is derived. The model predicts the intensity variation in the far field of the laser beam in the presence of the lensing medium and takes into account the aberrant nature of the thermal lens. Some experimental results which support the validity of this approach are presented.

Anomalous nuclear reactions in condensed matter: Recent results and open questions

We have observed clear signatures for neutron emission during deuteron infusion into metals, implying the occurrence of nuclear fusion in condensed matter near room temperature. The low-level nuclear phenomenon has been demonstrated in collaborative experiments at Brigham Young University, at the Gran Sasso laboratory in Italy, and at the Los Alamos National Laboratory. We have shown that neutron emission can be induced in metals using both electrochemical and variational temperature/pressure means to generate non-equilibrium conditions. Observed average neutron emission rates are approximately 0.04–0.4 no/s. Current efforts focus on trying to understand and control the phenomenon. In particular, we wish to understand the correlation of neutron yields with parameters such as hydrogen/metal ion ratio, pressure (induced, for example, by electrical field or gas pressure or mechanical pressure), temperature variation, hydride phase changes, and surface conditions, e.g., a palladium coating on titanium. We want to know if fusion arises due to the close proximity of the deuterons in the lattice (piezonuclear fusion), or possibly from “microscopic hot fusion”, accompanying strong electric fields at propagating cracks in the hydride. The latter interpretation would imply neutron emission in bursts. Our experiments show clear evidence for emission of ∼102 neutrons in bursts lasting <128 μs, although random neutron-singles emissions were also observed. Experiments now underway to compare thed−d, andp−d, andd−t reaction rates will be important to a consistent description of the new phenomenon. Careful scrutiny of this effect could increase our understanding of heat, helium-3, and tritium production in the earth, other planets, and even the stars.

In quest of a trigger mechanism for neutron emissions from deuterium/solid systems

The triggering of neutron emission in electrolysis experiments has not been achieved. (AIP)

An assessment of claims of 'excess heat' in 'cold fusion' calorimetry

Abstract Claims of ‘excess heat’ from measurements of the heat of electrolysis at several watts of power are largely based on use of poorly characterized, isoperibol, heat-conduction calorimeters with single-point temperature sensors. This paper describes construction, testing, and calibration of a calorimeter of similar design. Heat-conduction calorimeters with single-point temperature sensing and inadequate mixing are subject to large systematic errors resulting from non-uniform heat distribution within the system. Confirmation of electric-heater calibration by a chemical reaction with a well-known enthalpy change is a minimum requirement to insure accuracy. Improper or incomplete calibration is a probable cause for many claims of ‘excess heat’ in ‘cold fusion’ experiments.

Heating‐effect minimization in dye lasers

Optical pumping of dye lasers deposits heat nonuniformly in the active medium. Because the refractive index of a liquid or gas is a function of temperature, gradients are created which refract the laser beam. This effect is sometimes serious enough to quench laser action. In this paper, we evaluate the effects caused by optical pumping with a coaxial flashlamp and suggest ultraviolet absorbers and wavelength shifters as materials for minimizing the problem.

An emulsion dye laser

A laser dye which is insoluble in water has been dissolved in hexane and emulsified in a water matrix. When pumped with a nitrogen laser, this mixture was observed to lase. The emulsion is superior to a simple hexane solution because the excellent thermo‐optical properties of the water matrix help prevent refractive‐index gradients from degrading laser performance. This is a useful characteristic for flash‐pumped dye lasers, laser‐pumped dye lasers, and liquid filters. Another type of solvent system, a critical solution, is also discussed. For certain dyes, a critical solution has even better thermo‐optical properties because of its ability to absorb heat as it undergoes a liquid‐liquid phase transition.

Design Of High Performance Soft X-Ray Windows

Methods of designing strong, high transmission soft x-ray windows are discussed. A material which contains several elements, most notably 0, N, and C, produce the most spectrally neutral window. It is noted that a predominantly single element material such as diamond is in reality an edge filter. A structure to support very thin films and to provide exceptional mechanical strength is discussed. Pressure cycling data for such a supported window are presented.

Design and fabrication of heat resistant multilayers

Many promising applications of multilayer x-ray optical elements subject them to intense radiation. This paper discusses the selection of optimal pairs of materials to resist heat damage and presents simulations of multilayer performance under extreme heat loadings.

Liquid water cluster sizes

Abstract The effective mean number of water monomers per liquid cluster estimated from tensile strength and surface tension data appears to fall within the range, 4–20, while an estimate based upon a generalized thermodynamics varies from 8 to 5 over the range 10–50°C. This depends upon a new interpretation of surface tension. Since these clustering estimates are somewhat lower than some abstract theories have predicted, they may be regarded as tentative.

Measured response of multilayers to damaging fluxes.

We have measured the response of WC/C multilayers to x-ray fluxes on the order of 200 MW/cm2 using laser-generated plasmas and found that these multilayers will maintain near peak reflectivity for at least 1 ns but are eventually destroyed. A description of the experiments and data analysis methods is given. Transmission electron micrographs of WC/C multilayers before and after irradiation show melting to be the dominant damage mechanism. The results of the experiments will be compared with simulations.